The pseudo code:
      for(int i = 0; i < $max_iterations; i++) {
        body_fn(MlrtFture($tensor_list_or_flow_in[i]),
                MlrtPromise($tensor_list_or_flow_in[i+1]),
                i, i, $invariant_args);
      }

      return $tensor_list_or_flow_in[$max_iterations]
  }];

  let arguments = (ins
    TF_Tensor:$max_iterations,

    The pseudo code:
      for(int i = 0; i < $max_iterations; i++) {
        body_fn(MlrtFture($tensor_list_or_flow_in[i]),
                MlrtPromise($tensor_list_or_flow_in[i+1]),
                i, i, $invariant_args);
      }

      return $tensor_list_or_flow_in[$max_iterations]
  }];

  let arguments = (ins
    TFTensorType:$max_iterations,